Plaster of Paris

[tidwell@ix.netcom.com (Virginia Tidwell)]

Philip Bigelow asked about hardners for plaster of paris for use in 
molding and casting.  There is some excellent info. on the different 
types of gypsum plaster available for casting in the book:
           Vertebrate Paleontological Techniques Volume One,
             Patrick Leiggi, Peter May
              Cambridge University Press, 1994

Some of the recommended gypsom plasters include: White Hydrocal, 
Hydrocal FGR Gypsom Cement.

At DMNH we have received some casts from other museums that are plaster 
of paris with a small amount of marble dust added to the mix for 
strength.  We can certainly tell the difference in weight compared with 
regular plaster casts. 

             Hope this helped
                  Virginia Tidwell